Secure computer data storage method and device

ABSTRACT

A secure, tamper- and forgery-proof peripheral for the storage of authenticated, dated computer data with an evidential value. The invention is based on an optionally-rewritable, fully-integrated storage peripheral which is functionally protected by an electronic system which only authorizes the addition of data in the unused free space and prohibits the deletion, alteration or overwriting of pre-recorded data. At the end of each file-write operation, the date, which is provided by a non-modifiable internal clock that is calibrated only at the time of production, is associated therewith. Each device includes a unique integrated secret internal digital identifier which is associated with a unique public identifier and the identifiers are used to personalize the device and render same unreproducible. The association can be verified using several third methods which never divulge the secret internal identifier.

The present invention relates to methods and devices for secure,forgery-proof storage of computer data with the aim of ensuring theauthenticity of the recorded data at a given date and also to associatedprocesses and methods of production, verification, authentication anduse.

Traditionally, such systems are implemented on single-write storagedevices which are based on the ability of the medium used to bephysically altered in an irreversible manner. These media (fixed orgenerally removable) are easy to reproduce in full. By way of example,very common non-rewriteable discs of the CDR and DVDR type are not,generally, individually identified and can therefore be manipulated onan external system and be recopied integrally after forgery on anidentical blank medium. Similarly it is possible to corrupt therecording of a single-write medium by forcing rewriting over tracksalready comprising data, the reader-writer offering none or littleprotection against native access commands being sent to the medium.Unique identification of the medium often comes into conflict with theability to reproduce or forge and because the medium is notself-powered. Therefore overall it presents only a very low level ofsecurity. Magnetic media are more dense and of higher performance butare natively multiple-write, therefore even easier to corrupt.

One of the ways of compensating for the weaknesses of removable orrewriteable media is the use of cryptographic methods which effectivelyallow, at the moment of writing, authentication of the data but whichincrease the vulnerability to unique errors and often makes data sharingbetween users tedious. These often complex algorithmic methods do nothowever directly protect the medium and/or the reader, remain costly incalculation resources and are subject to obsolescence in the course oftime. If they prove to be effective and necessary in the transactionaldomain in real time, they present numerous disadvantages as soon aseither it is desired to use a large quantity of data or sharing of thedata between a plurality of users is necessary or the data must be keptfor several years. Access to the medium makes any cryptographic methodnull and void in any case, the medium being able to be duplicated andforged a posteriori.

The dating problem adds to the former, systems which date the filesoften displaying great vulnerability, and rarely preventing voluntary orinvoluntary corruption of the dates of the computer files. The structureof the file systems currently used is known and the associated dating isvery rarely protected or encrypted, therefore vulnerable.

The ultimate solution resides in using third bodies which store thedata, possibly encrypted, redundantly and ensure their physicalprotection. These methods can prove to be effective but are oftenlogistically expensive according to the quantity of data to betransmitted. They use communication links which may be unavailableand/or poorly protected public networks. Other similar solutions forauthenticating data involve digital signature methods, the third bodyonly keeping the signatures of the files. The authenticity can beestablished by comparison of signatures. This does not prevent problemsconnected to the possibility that the original data are voluntarily orinvoluntarily corrupted at the time or that the development of computersallows forgery thereof. Likewise, the use of such methods makes recourseto signature software necessary—itself vulnerable.

Each method cited covers a particular field of application and offers nosimple solution for recording with any autonomy internal, confidential,private or strategic data about an individual, a professional or anenterprise as soon as the quantity of data becomes large and must beable to be possibly presented or requisitioned as a posteriori authenticjuridical and legal evidence.

The physical or legal entity who owns them, manages them or isresponsible for them and does not necessarily have the wish or thetechnical and/or organisational means to transmit these data via—orto—an external third party because of their strategic, confidential orprivate nature.

The authorised or institutional bodies which, within the control orsearch framework, can request presentation of the data have no longerthe means of copying, authenticating or guaranteeing the data from allusers and are constrained to leave the care and control of the data tothose transmitting them.

The totality of vulnerabilities means that it is extremely difficult togive a legal value to private computer recordings based on standardelements, and that in a contradictory manner, it appears to be more andmore necessary to ensure the authenticity of data whatever they are,computer storage generally constituting the modern means of retaininginformation.

The method and the device according to the present invention seek tocompensate for the ease of reproduction and forgery of paper, audio,video and standard computer recordings, and the mastery of which isentirely ensured by the persons who store and control the information,and who can therefore forge it or shorten it, backdate it a posteriorior be victims of internal or external attack on these data. The factthat this information is private can make the cross-checking of certainunique items of information impossible, lengthy or tedious. Moreprecisely, the invention comprises a method for storing computer data,characterised in that it comprises integrating entirely in one device:

-   -   a data storage peripheral,    -   an adapted input-output controller transforming said data        storage peripheral into a single- or restricted-write storage        peripheral by diverting all input-output interface commands from        a host system to the internal interface of the integrated data        storage peripheral, in order:    -   to authorise exclusively the addition of new files in the free        space by dating them independently thanks to a secure internal        real time clock, and    -   to prohibit the deletion, alteration and rewriting of previously        written and hence prior dated data,    -   to protect the totality of said device on the one hand against        forgery or duplication by a unique secret internal identifier by        association with a unique public serial number, on the other        hand by a peripheral protection enclosure intended to prevent        intrusion into the equipment, the alteration of any component        and internal data, and also the analysis of the unique secret        identifier without compromising the validity and authenticity in        an irremediable manner,    -   to detect an intrusion, alteration and analysis attempt, said        detections being able to be verified by several third party        methods on said process, the latter being thus secure and        suitable for storing authenticated, dated computer data with an        evidential value.

According to an advantageous feature, the method according to theinvention comprises furthermore reproducing electronically andinternally said unique public serial number in order to allow electroniccontrol of the latter.

According to an advantageous feature, the method according to theinvention comprises furthermore physically protecting all the internalcomponents by leaving accessible only the external functionalinput-output and supply interfaces, thanks to a peripheral sealedenclosure encompassing all the components, formed by a passivemechanical and electromagnetic protection incorporating an activeintrusion detection sensor and the associated electronic system, thelatter ensuring the immediate destruction of the unique secret internalidentifier and the internal serial number if necessary, by instantaneousdeletion, in the case of voluntary or involuntary impairment changingthe vulnerability or the autonomy of the device, or any internalinvestigation attempt detected by the sensor being able to make itpossible to compromise, control, alter, analyse data, interfaces orinternal components.

According to an advantageous feature, the method according to theinvention comprises furthermore keeping active the internal real timeclock, the secret identifier, the internal serial number if necessaryand the electronic system for detection of intrusion and destruction,without any external supply source for the lifespan specified for theequipment, thanks to an autonomous internal supply sub-system, possiblybacked-up externally in order to extend the lifespan thereof.

According to an advantageous feature, the method according to theinvention comprises furthermore making it possible to guarantee theunique, unreproducible personalisation of the equipment whilstpublishing its existence, possibly before authentication, by generatingrandomly by calculation internally of the equipment, the unique secretidentifier, by calculating internally a one-way digital fingerprint ofthis identifier which does not allow return to the latter, byestablishing the uniqueness of the fingerprint by interrogation of apublic database containing the fingerprints of the totality of existingequipment, the identifier being recalculated if there is a clash and thedevice being formally identified as soon as the fingerprint is unique,by adding therefore into the public database the references of theequipment: unique serial number and fingerprint.

According to an advantageous feature, the method according to theinvention comprises furthermore ensuring the authenticity of the deviceafter manufacture, the test, the final assembly and the activation ofthe peripheral protection, until acquisition by the end user, by makingunique the operations for assigning the unique serial number, thesynchronisation of the real time clock relative to an external trustedtime reference, internal self-generation of the unique secretidentifier, the external copy of the unique secret identifier in asecure environment of the unique secret identifier to an authenticatingbody entitled to guarantee the secrecy of this identifier and in factthe authenticity of the equipment, the uniqueness of each operationbeing guaranteed by design by inhibiting or destroying, in anirreversible manner and as soon as possible in the initialisationsequence, the material elements and/or the micro-code allowing thisinitialisation.

According to an advantageous feature, the method according to theinvention comprises furthermore allowing without limitation on theoccurrence, the preliminary verification of the authenticity and of theintegrity, by checking and cross-checking unique listed serial numbersin the public database, by checking the validity and the progress of theinternal clock relative to an external trusted time reference, takinginto account the maximum specified drift of the internal clock, and byvisual or non-destructive checking of the integrity of the externalcasing.

According to an advantageous feature, the method according to theinvention comprises furthermore allowing authorised bodies toauthenticate the equipment upon request by verification via third partymethods using the secret internal identifier without revealing it, byinternally recalculating dynamically the fingerprint of the identifierand by directly interrogating the public database, or by internallyconnecting the secret identifier to the internal date and to an externalmessage provided before internal calculation of the fingerprint of thetotality, the totality of known elements being provided forauthentication remotely by the entitled authenticating body which alonecan verify the consistency thanks to the copy of the unique secretidentifier which it has, these functions involving the secret identifierbeing temporised and limited in occurrence internally of the equipmentin order to avoid inverse determination of the identifier by analysis orsuccessive attempts.

According to an advantageous feature, the method according to theinvention comprises furthermore allowing the authenticating body itselfto authenticate the equipment under its control and as a last resort byinjecting its copy of the secret identifier for comparison internally ofthe equipment which detects perfect similarity, and sends in reply aunique message which can be verified by said authenticating body, thisfunction involving the secret identifier being temporised and limited inoccurrence internally of the equipment in order to avoid inversedetermination of the identifier by analysis or successive attempts.

According to an advantageous feature, the method according to theinvention comprises furthermore allowing, by way of variant which is notnecessarily implemented, managing autonomously the expiry of data in thepast, by authorising—solely in the case of complete filling of theinternal storage peripheral—writing of new files by zapping, withinsufficient limits and in chronological order, data prior to a relativedate, updated dynamically relative to the current date provided by theinternal clock, departing thus from the single-write rule withouthowever compromising or altering the useful data which are still validand dated subsequently to the expiry date.

According to an advantageous feature, the method according to theinvention comprises furthermore presenting any internal parameter andindicator which is characteristic of and specific to said device in theform of virtual files in reserved names, seen by the host system asstandard files and avoiding using drivers or particular operating modesat the level of the host system for management, administration andmonitoring of said device.

According to an advantageous feature, the method according to theinvention comprises furthermore partitioning said data storageperipheral with a different expiry duration by partitioning.

The present invention relates furthermore to a device for storingcomputer data, characterised in that it integrates in full:

-   -   a data storage peripheral comprising an internal interface,    -   an adapted input-output controller,    -   an input-output interface,    -   a secure internal real time clock,    -   a unique secret internal identifier,    -   a unique public serial number,    -   a peripheral protection enclosure,        said adapted input-output controller being able to transform        said data storage peripheral into a single- or restricted-write        storage peripheral by diverting all input-output interface        commands from a host system to the internal interface of the        integrated peripheral, in order:    -   to authorise exclusively the addition of new files in the free        space by dating them independently thanks to the secure internal        real time clock, and    -   to prohibit the deletion, alteration and rewriting of previously        written and hence prior dated data,        the totality of said device being protected on the one hand        against forgery or duplication by the unique secret internal        identifier by association with the unique public serial number,        on the other hand by the peripheral protection enclosure        preventing intrusion into the equipment, the alteration of any        component and internal data, and also the analysis of the unique        secret identifier without compromising the validity and        authenticity in an irremediable manner, intrusion, alteration        and analysis attempts being able to be verified by several third        party means on the totality of said device, the latter being        thus secure, inviolable and forgery-proof, suitable for storing        authenticated, dated computer data with an evidential value.

The device according to the present invention is integrally protectedagainst rewriting and able to give an authentic, evidential and/or legaland/or juridical value to the digital data. The data are recorded in anirreversible and dated manner with sufficient precision in an entirelyautonomous manner. The device is self-protected and identified in aunique manner. Any attempt to alter or compromise the device results inits invalidation. Identical duplication of the device is made reasonablyimpossible.

Use of the device allows, without specific constraint and without usinga third party during its use, any person anxious to be able to establishhis good faith and the legality of his activity, to do this by leavinghim free will over the data which he wishes or must thus protect. Thedevice does not in any case prevent dissimulation, complete destructionof data, of information or evidence nor possible a priori forgery in allcases, but establishes a posteriori that the data, when they arepresented, have indeed been recorded at the indicated date, and have notbeen able to be forged or replaced subsequently.

The originality of the device is that its operating principle isindependent of any clumsy cryptographic method, which is subject toobsolescence or expiry due to unforeseeable progress in crypto-analysis.Cryptography is not necessary in the sense where the user controls andphysically possesses the device, and must decide upon the degree ofconfidentiality and protection of the data independently of the physicalstorage peripheral which he is using. It minimises the intervention ofthird parties for authentication of the data, allows the transmission ofstrategic or critical information on third party networks at a distanceto be avoided, and in fact allows more data to be protected, ortransmission of paper or microfilm data to a computer medium which iseasier to use and to archive.

The importance of the described device is the possibility of using as aphysical storage element any rewritable or non-random access dataperipheral without impairing the performance, reliability orenvironmental resistance and giving it a neutral transparent behaviourrelative to the host system, thus leaving the end user the freedom touse the external software compression methods, cryptographic protectionand reliable storage put at his disposal.

The device which is the subject of the invention includes theconstituent peripheral equipment (termed subsequently equipment), butlikewise the methods and processes which permit manufacture andverification of the equipment by third parties, and the description ofcertain particular modes of operation.

The device integrates in full a standard commercial data storageperipheral with a removable medium or one made removable (by way ofnon-limiting example: a magnetic technology hard disk, a flash memorydisk, a CD/DVD writer, the ejection mechanism of which is de-activated,loaded with a writable medium), the interface of which is protected andisolated by a specific controller, limiting by design the storageoperations to the single function of adding data. The equipment is seena priori by a host computer system as peripheral computer storageequipment, except that it is functionally impossible to alter, delete orto rewrite previously written logic recordings. It is only possible toread them. A dating clock calibrated during manufacture, which isnon-alterable and autonomous, dates any recorded file in real time andindependently of the host system. Dating of the files is recorded by theelectronic control system on the internal peripheral, either in additionto the recording of the user data with a reference to the basicdescriptor of the logic or file recording with which it is associated asmetadata, or in the descriptor itself of the file in place of datinginformation normally provided by the host system, or in the unused ornon-specified spaces of this file descriptor. The totality of thisdating information is accessible in read only to the host system whichallows verification of the dating authenticated by the device for eachwritten recording.

The equipment behaves overall like a single-write type peripheral whichre-dates the information relative to a relative reference time which issufficiently precise, and the drift of which can be measured, and evenauthenticated. The integrated peripheral is therefore only filled as ifit included a physically non-rewriteable medium.

By way of a variant which is not necessarily implemented and under veryrestrictive conditions, the equipment can easily administer an expirydate in the past relative to its internal clock, therefore at its owndating which possibly allows the space occupied by obsolete data to befreed in order to write new recordings when the peripheral is ‘full’.This functionality termed ‘expiry’ makes it possible to fulfil thespecific data storage needs for a short lifespan before the overalllifespan of the equipment which presents an interest in certainapplication fields.

An autonomous identification electronic sub-system contains theauthentication elements of the equipment which are unique and keptsecret and prevents duplication or production of false equipment fromnew parts or those recovered from voluntarily compromised equipment. Theunique internal identification elements are systematically destroyedduring non-authorised physical access attempts. An active peripheralprotection enclosure integrally protects the totality physically anddetects any penetration or intrusion or investigation attempt with theaim of compromising the integrity of the equipment, of accessinginternal interfaces which make it possible to alter the data and toextract the identifiers therefrom. In the case of an intrusion attempt,the equipment instantaneously and in an irreversible manner destroys theunique identification elements and possibly the clock. The equipment isinvalidated and is returned into an initial mode which continues toprotect the written data on the storage peripheral without destructionof the equipment, by invalidating any writing operation. The data remainreadable in all circumstances.

Any equipment, the integrity of which can be confirmed bynon-destructive analysis methods which are available (essentially theverification of the unique identification elements), ensures thevalidity and authenticity of data read on the internal peripheral.

In the case of doubt or suspicion, the entitled authenticating bodyhaving, itself alone, a copy of the secret identifier, can submit thecopy of the secret identifier which it has to the equipment which itselfeffects the internal comparison or allows a third authorised party toverify indirectly this identifier while limiting the request intervalsin order to avoid its determination by, by way of non-limiting example,using a brute force or screening or targeted analysis method.

In the case of a critical internal crash, the voluntary dismantling ofthe equipment can be effected in order to make an assessment of it or toeffect the recovery of the data following the manufacturer'sinstructions. With this aim, a procedure must be able to allow simplecut-out of the equipment which has the effect of instantaneousinvalidation of the authenticity, then the extraction without impairmentof the internal storage peripheral, but allows access directly to thelatter, to the data which is a priori non-encrypted by the equipment andpossibly to the medium.

Any damaged or corrupted equipment loses its authentic value: thepresent data are no longer guaranteed any more than if they had beenstored on any non-secure medium, in contrast they remain accessible atleast for reading as long as the equipment is functional.

As with any security method, the probability of non-detection ofintrusion or the possibility of duplication of the equipment is madenegligible but not nil and is reduced to the reasonable minimum as afunction of the intended objective cost and the required level ofprotection.

The present invention includes the methods and the sequencing ofoperations subsequent to the material manufacture of the equipment,which ensure in an irreversible manner after sealing of the protectivecasing of the equipment:

-   -   sure and incorruptible dating,    -   unique secret identification,        whilst making independent the manufacturer of the equipment, the        entitled authenticating body (by way of example one for each        nation, consortium, community) and the end user.

The present invention includes several processes or methods forverification associated with the formal authentication of the equipmentaccording to the invention. These processes or methods for verifying theauthenticity use or do not use external third parties, and/or use or donot use the secret internal identification.

Other features and advantages will appear in the text which follows ofseveral examples of embodiments of methods and devices according to theinvention, accompanied by the annexed drawings, examples which are givenby way of illustration and non-limiting.

According to a particular embodiment, the device is administered andconfigured using a method of virtual files, seen by the host system asstandard files present on the integrated peripheral. This methodpresents any parameter and internal indicator which is characteristicand specific to the described device in the form of reserved name filesaccessible in a standard manner by the host system, avoiding the use ofdrivers or particular operating modes at the level of the host systemfor management, administration and monitoring of the device anddescribed variants and options.

FIG. 1 represents an overall operating diagram of the equipment,

FIG. 2 illustrates the role of external third parties,

FIG. 3 illustrates a suggestion for file structures with dating byadding metadata,

FIG. 4 illustrates a suggestion for file structures with dating byreplacement in the file descriptor,

FIG. 5 illustrates the secure initialisation and identification processof each piece of equipment individually by the manufacturer,

FIG. 6 illustrates the secure process of authentication of each piece ofequipment,

FIG. 7 illustrates the secure process for activation by the end user,

FIG. 8 illustrates the various authentication methods and processesconnected with production of the described device.

FIG. 9 illustrates the various assessment methods of the equipment,

FIG. 10 illustrates the suggestion for using virtual files in order toadminister the equipment,

FIGS. 11 to 13 illustrate the filling of the medium,

FIGS. 14 to 16 illustrate the filling of the medium with positioning ofthe expiry mechanism,

FIG. 17 represents a detailed diagram for a production suggestion.

The sign [u] on certain Figures signifies that the action isfunctionally unique and irreversible. Certain signs are intentionallyworded in English in order to conform with usage of the technology.

The device which is the subject of the invention integrates one or anassembly of standard peripherals for storing computer data 1. Thisperipheral is isolated from the host system by a controller 2 whichlimits the operation to adding data and ensures independent dating ofthe stored data thanks to an internal clock 6. The device comprises apair of unique electronic digital identifiers 7, 8 which preventduplication of the equipment. The assembly is protected by an activetamper respondent enclosure 10 which destroys the unique secretidentification elements in the case of an attempt at tampering. Thedevice is then invalidated and loses its authenticity.

The integrated peripheral 1 is a read-write model, no prerequisite beingnecessary concerning the possibility or not of deleting or re-writingthe data (by way of non-limiting example a magnetic hard disk, a flashdisk).

Generally, such peripherals address physical storage elements termedcommunally blocks, which are classically numbered in sequence, and logicstorage elements of a higher level which can be manipulated by a systemor host computer termed communally files, directories. All theseentities are often accessible sequentially or randomly in read and inwrite. A storage peripheral normally has no knowledge of the logiclevel, managed entirely by the host system via a system of files (FileSystem) subject to strict and easily analysable specifications.

With the aim of simplifying the language, we will term blocks thephysical entities addressable by the peripheral and files the logicentities manipulated by the host system, without detailing the conceptsof recording, clusters, directories and associated attributes.

The functional interface 3 of the integrated storage peripheral 1 allowsa priori any operation: classically, addressing, writing and reading ofblocks, and uses a priori no protection nor limitation on thesefunctions. This interface is isolated functionally by an activeintelligent controller 2 with an external interface 13 emulating a datastorage peripheral of a substantially lesser capacity than the capacityof the real system. The physical input/output interfaces 13 and 3 do notnecessarily have to be identical, just as the peripheral recognised bythe host system 20 does not have to be identical to the peripheral 1which is actually integrated, even if, in practice, the similarity onthis precise point can simplify the overall functioning.

When it is supplied externally with electricity 14, the equipment is inits nominal operating mode. The controller 2 translates in real time anyaddressing, reading and writing request from the external interface 13to the internal interface 3. The data themselves are not processed, norcompressed nor encrypted and are stored as such if authorisation towrite them on the integrated peripheral 1 is validated by the controller2 which has a basic knowledge of the logic storage level, therefore ofthe structure of the files and directories.

In its nominal operating mode, the controller protects the data againstre-writing thus emulating a storage system ‘with addition only’: At theend of manufacture, the equipment is devoid of user data andpre-formatted therefore able to receive data. Overall, it thereforemaintains a partition between the ‘occupied’ space 4 and the ‘free’space 5. By way of non-limiting example of implementation, it maintainsa ‘pointer’ 15 which indicates from which block of data the writing ofnew blocks is possible and overall inhibits any writing to the precedingblocks. In actual implementation, the partitioning can be more complexas a function of the system of logic files used, which itself can imposespecific partitioning between physical and logic information, asrepresented in FIG. 17, being able to necessitate the simultaneousmanagement of several pointers. Access to the physical memory istherefore random in read in the occupied space 4, and purely sequentialin write in the free space 5. An attempt to delete, alter or re-write afile or previously written data results therefore in an error reportedto the host system 20, thus signalling the impossibility of effectingthe desired operation on the emulated peripheral. Writing new data, newfiles or creating new directories is possible, the storage peripheral istherefore filled inexorably up to its maximum useful capacity andrejects the writing of files which exceed the remaining size. It istherefore ‘full’ and must be completed or replaced by identicalequipment since it is operationally impossible to delete the writtenfiles. It can then be disconnected and physically archived without anysupply 14 external to the apparatus during the storage duration of thelatter, an internal supply sub-system via batteries 19 making possiblemaintenance of critical internal elements (clock, identifiers, pointers. . . ) purely by way of indication, between ten years and twenty yearsaccording to the lifespan of the internal elements which are subject toageing or are perishable, such as the batteries. Storing for longerdurations can dictate either the use of auxiliary external batteries,taking the place of internal batteries, or certified transmission ofthese data with their date of creation to new equipment.

The written data are protected against any electronic attack (virus,malice, forgery . . . ) since they cannot be rewritten or altered bydesign. The destruction of data implies destruction of the equipment.

The controller 2 is specifically adapted to the structure of a standardfile system (by way of non-limiting example, FAT, NTFS, UDF, NFS, HFS,sequential . . . ), or to the structure of a proprietary file system inthe case where the equipment is to ensure compatibility with a pluralityof different standard file systems. The file system creates the linkbetween logic storage and physical data storage. The controller 2detects by analysis sent write orders, the end of a logic storageoperation (by way of example, the end of writing a file, or the creationof a directory entry). The sequential nature of writing data, withoutthe possibility of deletion, greatly simplifies this task.

At the end of a successful logic writing operation, the controllereffects the following tasks in an autonomous manner:

-   -   irreversible protection of the storage elements used for the        file descriptor 24, and for the data themselves 25, by        reservation of used blocks, for example tabulation and/or        pointing 15 into a safeguarded memory which is accessible to the        controller, and by redundancy over a reserved space on the        storage peripheral itself.    -   independent dating 26, thanks to the internal reference dating        clock 6, either by writing supplementary blocks of masked        metadata to the host computer 28, as represented in FIG. 3, or        by rewriting this date in place of the date written by the file        system in the file descriptor 24 as defined by the used file        system, as represented in FIG. 4.

The written data are dated to the second in an autonomous mannerrelative to the internal clock 6 of the device, by the equipment itself,independently of the host file system which applies its own dating,often not so certainly and reliably. This internal dating isirreversible and forgery-proof, the internal clock being set to timeonce during manufacture and not being able materially to be resettimewise subsequently, and the recordings comprising these data beingprotected against rewriting. The precision of the dating is basedentirely on the precision and the drift of this internal clock which canbe correlated externally without however the possibility of correctingit. The dating is effected in universal time.

In the case where the device imposes the dating by adding metadata 28,the latter are made invisible in normal use of the files and arethemselves protected against rewriting. The metadata are at leastcomposed of a pointer 27 allowing access to the descriptor of the fileor of the directory and a structure comprising the internal date andtime 26 at the end of writing. The totality of metadata of the totalityof written files is addressed in a ‘system’ file 29 which is accessiblein read only. A tool or else the analysis of this file makes it possibleto correlate the metadata and the user files and therefore to verify theinternal date which the device had assigned to each file duringrecording which is only authentic by design.

In the case where the device imposes the dating of the files byreplacement 26 of the date of creation in the descriptor 24 of the file,in conformity with the demands of the file system which is used, thebehaviour of the device is perfectly standard. The date imposed by theequipment differs from the system date and can, in the case of apractical concern, be corrected dynamically internally at the moment ofreading in order to take into account the difference between local timeand universal time (time zone). Most file systems currently used managea plurality of dates (by way of example the alteration date which isuseless in our case), it is therefore possible also to keep the date ofthe external system as purely indicative.

The equipment is itself made forgery-proof thanks to a uniqueidentification method implemented internally of the equipment. It isreasonably impossible to duplicate the equipment without the completeknowledge of the unique identification which is never divulged by thedevice, outwith an initialisation phase or solely an entitledauthenticating body 22 receives the integral copy of this identifier,one part of which remains kept secret. The identification elements aredestroyed as soon as an intrusion, tampering or compromising attempt onthe equipment is detected. The identification is used only forvalidation and authentication of the equipment and has no operationalrole for the end user.

The identification system is composed of the following elements:

-   -   unique public identification element 8, 18: serial number of the        entire equipment, marked visibly and indelibly on the equipment        18 and reproduced electronically internally 8 for reasons of        facility of use and direct authentication.    -   unique secret identification element 7 generated and stored        imperatively internally of the equipment and verifiable solely        by third party methods which never distribute this identifier.    -   optionally manufacturer identification elements, not shown: by        way of example, electronic or marked serial number of the        internal components, date code, batch numbers, inspection        numbers, often indicated by the manufacturer within the scope of        its quality system, which depend upon use and which may allow        verifications or supplementary reports possibly after        dismantling of the equipment.

The association between the public identifier and the secret identifieris known solely by an entitled third party authenticating body 22 whichis involved at the end of the manufacturing process. The secretidentifier is distributed once and once only 17 outwith the equipmentfor the attention of this single body 22 which preserves the totality ofthe information relating to the totality of equipment which it managesand authenticates.

This body is the only third party which is involved in theauthentication of each piece of equipment, solely initially at the endof manufacture of the equipment and possibly during use in the case ofextensive inspection of the authenticity of the equipment if doubtpersists about this authenticity or if the stakes or the legislatorjustifies such recourse.

The unique electronic identifiers of the equipment 7, 8 (except formanufacturer identification numbers which are not described becauselinked to the implementation and components used) are stored in asafeguarded volatile memory circuit by battery 19 and having a rapidinternal and/or external delete function 9. The absence or inconsistencyof one of these identifiers indicates the compromising of the equipment.

Only a one-way fingerprint 23 of the unique secret identifier associatedwith the serial number 18 of the equipment is distributed publicly 21outwith the entitled authenticating body or bodies 22 which alone haveaccess to the association between the serial number 18 and a copy 17 ofthe unique secret identifier.

The unique secret identifier is a long length binary message (by way ofexample 4096 bits or more), certain values being able to be reserved andnot being able to be used.

The internal clock 6 is set at universal time once during manufacture ofthe product relative to an authenticated reference clock 16, and cannotbe subsequently reset timewise by design without corruption of otherintegrity parameters of the system.

The system thus described has validity only if it is physicallyself-protected against tampering and internal analysis. To this end, thedescribed assembly is integrally confined in a protective enclosure 10by a peripheral sensor 12 which is sensitive to intrusion, supplied by abattery 19 having a long life span (by way of example, lithium battery).Any attempt at penetration and internal analysis by a microprobe is, onthe one hand, made extremely difficult by external mechanical andelectromagnetic protection 11 and, on the other hand, triggers an alarmin the case of penetration beyond a limit casing 12 which encompassesany functional component of the equipment. The alarm results in theinstantaneous destruction 9 (deletion/resetting to zero) of the internalidentifiers 7, 8, making the equipment non-replicable thanks to theinaccessible secret part 7 which cannot be analysed without penetratinginto the equipment, therefore without triggering the alarm.

The equipment is integrally protected by an active physical enclosurewhich ensures protection against intrusion by any known method,standardised in certain countries for the protection ofsecurity-critical parameters and/or cryptographic modules (by way ofexample in the United States FIPS 140-2 standards or internationallystandard ISO 15408/Common Criteria AVL). The use of such methods can bemade very cheap by manufacturing in series, even for the highest levelsof security. Such sensors exist commercially (by way of example the D³sensors of Gore brand, FIPS 140 certified, level 4) and their generalprincipal is described purely informatively for clarification, referringat times to FIG. 17. Classically, the peripheral protection 10 iscomposed of an external mechanical protection 11 or sealed external box(by way of example in metal which is machined, moulded, folded,assembled, so that it cannot be dismantled, by welding, crimping)leaving room solely for functional interfaces for communication andsupply, and a sensitive sensor 12 detecting intrusion (piercing,machining, mechanical, electrical or laser, selective chemical attack)by altering an electrical parameter (resistor 121 and/or capacitor 122and/or contact 123). Often, this sensor is produced on the basis of anetwork of conductors and insulators which are sensitive to cutting,breaks and short circuits, covering the entire enclosure to be protectedin a uniform manner, and provided with ‘baffles’ in order to protect theexternal operating interfaces. The electronic alarm and detection system118 is low consumption in order to be able to ensure great autonomy forthe protection supplied in an autonomous manner by battery 124.Normally, the totality of the electronic system and of the internalcomponents is sunk in a resin 130 which is intended to ensure thethermal conduction in the absence of internal convection and prohibitingdirect access to the components or the internal signals. The aim of theprotection system is to prevent the insertion of a micro-probe making itpossible to analyse or control directly internal electrical interfaceswhich allow alteration of the protected data, analysis of the elementswhich are kept secret with a view to their duplication.

In order to eliminate any thermal attack, a temperature sensor 120analyses excessively high or low temperatures which can inhibit or limitthe effectiveness of the sensor.

The failure of the batteries 124 immediately places the system in astate of alert.

The protection likewise includes external electrical interfaces inexcess voltage/excess current frequencies or signals outwithspecification 129. In order to facilitate the protection, the operatinginterfaces are reduced to the minimum by the use of rapid seriesoperating buses (by way of example reflecting the current state oftechnology FireWire/i-Link/IEEE1394, USB, Serial ATA, Ethernet), of acontinuous external supply and static state interfaces of the system.

In the particular case of use of a hard magnetic disk which must operateunder atmospheric pressure, the operating depressurisation capsule ofthe disk is carried externally thanks to an integrated tube allowingfree passage of air without increasing the vulnerability of the externalprotection 132.

The intrusion detection in the enclosure results in the destruction ofthe integrity parameters 7, 8 of the equipment by instantaneous deletion119, 9 of memories 112 safeguarded by internal battery 113, 19, thisbeing the case whether the device is supplied externally or not. Thisdestruction of the identification parameters of the system does notprevent access in read to the totality of the data. The controller 2continues to protect the data, which lose their authentic value as soonas the equipment is reported to be compromised.

The equipment is designed to be autonomous in normal use. It does nottherefore assume any intervention by third party authenticators for use,and in fact makes it possible, to be used in an entirely private mannerwithout prejudging the possibility or the wish of the end user, toauthorise direct or indirect access to an external network.

The following part describes the methods and processes used in theinitialisation phase which makes it possible to move fromnon-personalised neutral equipment 30 coming from the manufacturer, tounique authenticated equipment 55 which is then operational at the placeof the end user 60.

At the end of assembly the equipment is completely integrated andprotected, the peripheral protection 10, 9 is activated. It is in aneutral initialisation state where the internal numbers are blank and aninitialisation micro-code is pre-loaded in the random access memory 107of the controller. An internal state logic machine 117 can assist thematerial protection of the non-alterable resources. The functionaloperating programme is the one which is loaded in the permanent orprogrammable memory in a unique manner 106 and is not alterable. Thecontent of all the internal memories can be analysed and verified at anytime. At the end of the initialisation, the initialisation programme isintegrally deleted, the random access memory can no longer be used torun any programme and serves only for temporary storage of internaldata. By way of suggestion, the initialisation programme is deletedgradually at each stage of the initialisation which ensures theuniqueness of the operations.

At power-up, the operating programme detects the initialisation stateand runs the initialisation sequence or picks it up at the currentstage.

The initialisation sequencing unfolds in three phases:

-   -   the personalisation phase, as represented in FIG. 5,    -   the authentication phase, as represented in FIG. 6,    -   the activation phase, as represented in FIG. 7.

As long as these three phases are not completed, the equipment isinoperative as storage peripheral, and no addressing, read or writeoperation on the internal peripheral is authorised.

The following description illustrates a sequencing suggestion.

The personalisation phase comprises the following operations startingfrom the neutral equipment 30:

-   -   31: Marking of the unique serial number externally 18 in the        structure of the box for the equipment (external protection        casing) in an indelible manner (by way of example marking by        laser or mechanical engraving).    -   32: Input of the serial number in electronic form via the        external interface.    -   33: Copy of the serial number 8 into the identification memory.    -   34: Input of the date and the reference time, relative to a        calibrated and certified external reference time 16 (atomic        clock and/or time server). The date and the time are programmed        in universal time.    -   35: Synchronisation of the internal dating clock to less than a        fraction of a second. By design, the time setting can only be        effected once.    -   36: Random generation internally of the equipment of two        passwords: these optional passwords make it possible to ensure        minimum protection of the equipment and are single use: they        allow protection of the equipment during storage or transit        phases. The passwords are transmitted once only by the interface        to the manufacturer 37 and 38 who transmits them independently        to the entitled authenticating body and to the end user.    -   39: Self-generation of the secret identifier, internally of the        equipment: a random generator calculates a long length        identifier: in order to avoid any analysis, the encoding is over        a number of bits such that the interrogation of the equipment        for analysis of the secret identifier, is unimaginable by any        screening or brute force methods, reducing the probability of        finding this identifier by chance to an improbable value and        this being the case even knowing the association between the        provided third party elements (signatures) and the unique        identifier. This identifier is stored in a volatile random        access memory safeguarded by battery, destroyed instantaneously        in the case of tampering.    -   40: Calculation of a one-way digital fingerprint, by a cutting        algorithm (for example SHA1), relocating a one-way summary 23 of        a few tens of octets (20 in the case of SHA1, standardised        cutting algorithm FIPS 180-2) from a minimal message of some        hundreds of octets (512 in the case of SHA1).    -   41: The equipment delivers the calculated digital fingerprint        with the internal serial number for verification of uniqueness.        To this end, a central 21, public database contains the totality        of the serial numbers of the totality of produced equipment and        used fingerprints. The interrogation makes it possible to know        if-the identification is unique by means of an indirect method        (fingerprint) which reveals no direct information about the        secret internal identifier 7. Only the manufacturers can enter        this information into the base which is public for consultation.    -   42: If the fingerprint is already being used, there is doubt        about the uniqueness, a message is sent to the equipment in        order that it submits a new identification.    -   43: If not, the database 21 is updated, and the initialisation        process can continue.    -   44: All the manufacturer initialisation functions are then        materially inhibited, for example by deletion (replacement by a        zero instruction (NOP)) of the totality of the code situated in        RAM which allowed this part of the initialisation to be        effected, and possibly by inhibition of this memory space for        subsequent running of programmes.    -   45: The equipment is, from now on, identified, and can be sent        and/or made available to the authenticating body 22, alone        entitled to know the association between the serial number and        the unique identifier.

By way of example, a secret message of 4096 bits (512 octets) seems togive a quasi-total invulnerability to the system. At a rate of oneinterrogation per day, limited in occurrence by the equipment itself,approximately 12 years is necessary to recover 4096 differentfingerprints which, despite everything, would not make it possible toreturn to the source, the normal fingerprints being ‘mathematically’one-way and each having an enormous number of digital antecedents(>10¹⁰⁰), and an infinitesimal probability of clashing (<10⁻⁵⁰), sizeswhich constitute in themselves ‘physical infinities’.

The authentication phase then begins:

The entitled authentication body 22 receives in an independent mannerthe identified equipment 45 and the interrogation password 37.

-   -   46: Input of authenticating password 37.    -   47: Unique transmission of the unique secret identifier 7 over        the operating interface.    -   48: Preservation of a copy of the unique secret identifier 17 by        the entitled authenticating body, associated with the serial        number 8.    -   49: Calculation of the fingerprint of the copy 17 according to        the method used in the equipment 40.    -   50: Interrogation and updating of the state of authentication by        request in the public identification database 21.    -   51: Confirmation of the association between the two fingerprints        of the internal identifier and its copy.    -   54: In the case of failure of association, or impossibility of        effecting the operation, the equipment is corrupted and must be        rejected and dismantled 53, either because the equipment has        already issued the unique identifier in an uncontrolled manner,        or because it has crashed. The authenticating body then        publishes the rejection of the numbered equipment in the public        database 21.    -   55: In the case of success, the entitled body declares        authentication of the equipment and publishes the latter in the        public database 21.    -   52: The internal authenticating password is deleted and also the        programmes and associated initialisation functions.

Only the entitled authenticating bodies can alter the state ofauthentication of equipment in the public database.

The entitled authenticating body guarantees the secrecy of theassociation between the public and secret identifiers, and can establishin the case of doubt and as a last resort the authenticity of theequipment. The entitled authenticating body and the manufacturer can becompletely independent. There may be several manufacturers and severalentitled authenticating bodies authorised by different authoritiesgiving authentic value to the equipment. The entitled authenticatingbodies can possibly share between them copies of the unique secretidentifiers.

The equipment is then authenticated. It can be marketed and delivered toan end user who can make use of it after activation.

The end user who acquires the authenticated equipment 55 receivesindependently the initial password 38 issued by the manufacturer, andmust activate it:

-   -   56: At the first power-up, he must connect the equipment and        must enter the provided password.    -   57: The initialisation functions are then all invalidated: only        the operating programme remains in place and can be run from        this moment.    -   58: The equipment is functionally activated.    -   59: This state is indicated visually even without external        supply (by way of example low ratio cyclic flashing of an LED        type light supplied by battery).    -   60: Once the equipment is activated, the end user can use the        equipment as a partitioned computer storage peripheral which is        initially blank.

He can himself verify the authenticity and the validity of his equipmentby the clarified methods.

This methodology guarantees however that no equipment can be diverted,removed or set up without checking and authentication.

The following part describes the methods which make it possible toestablish the validity and authenticity of the equipment, made availableto the end user and authorised authorities which are entitled to effectthe checking of the equipment and recorded authenticated data.

The equipment and its unique identification being protected physicallyby the protection enclosure 10, the probability that a user can presentequipment which is voluntarily corrupted and has an authenticappearance, is infinitesimal, however even this extreme case is cateredfor.

The failure of one of these methods indicates that the equipment isinvalid, the success of a method being able to be elaborated by anothermethod in the case of doubt persisting about the authenticity of theequipment.

-   -   Elementary methods not limited in occurrence:    -   61: Verification by comparison of the internal serial number 8        and the external serial number 18.    -   62: Verification of conformity of the equipment identified by        its serial number 18 in the public database 21.    -   63: Verification of the progress of the internal clock 6.    -   64: Verification of the consistency of the internal clock 6        relative to an external reference 16, taking into account the        specified drift of the internal clock.    -   65: Visual verification of integrity.    -   Third party methods involving the unique secret identifier 7        internally, made upon request and temporised internally in order        to avoid any analysis of the identifier (for example, limited to        one request per 24h):    -   67: Internal recalculation of the digital fingerprint 66 of the        unique secret internal identifier 7 and verification with        respect to the public database 2 1.    -   71: Internal calculation of the digital fingerprint of an        external message 68 (for example a certificate) provided by an        authorised body which is authorised to check the equipment, of a        length at least equal to that of the unique identifier and mixed        in a determinist but irreversible manner 70 with the unique        secret internal identifier 7 and possibly the internal date 6        before calculation of the fingerprint of the overall result 66.        The calculation elements 68, 6, the serial number 8 and the        result are supplied to the entitled authenticating body 22 which        keeps the copy of the secret identifier 17, which is therefore        alone able to establish the consistency of the totality, and        which confirms the authenticity to the applicant after        verification.

The fact that the message 68 identifies the requesting body in a uniqueand self-consistent manner allows the authenticating body to limit therequests only to authorities which are authorised to effect the checks.The equipment for its part accepts a priori any message or requestwithout prejudgement about the nature or the content of the message.

-   -   Direct method for checking the unique secret identifier:    -   72: Verification of the unique internal identifier directly by        the entitled authenticating body. It is similar to the preceding        method, except that the message which is provided is precisely        the unique identifier 17. Exact correspondence is detected        internally of the equipment 69 which provides as a response in a        particular case a fingerprint which is calculated 66 uniquely on        the basis of the unique identifier 7 and of the internal date 6.    -   Non-destructive assessment methods allowing a more detailed        analysis using the following methods:    -   73: Dumping of internal memories (apart from secret identifier):        ROM (Read Only Memory) 106, RAM (Random Access Memory) 107 or        any other rewriteable memory (Flash).    -   74: Dumping of any manufacturer identification number from        internal components accessible in electronic form. By way of        example: models, inspections, unique serial numbers of the        components used, binary code of the programmable components.

Destructive assessment methods demanding controlled dismantling of theequipment after, if possible, controlled copy of the data on anothermedium.

-   -   75: The equipment is arranged in order to allow simple        mechanical cut-out in order to allow direct access to the native        electrical interfaces 76 of the internal storage peripheral 1,        and to other elements 77 for assessment. This destructive        operation instantaneously invalidates the authenticity and any        other functionality.

As a suggestion for implementation, all these methods can use virtualfiles managed directly by the controller, and appearing as filesavailable on the peripheral, whilst they are not in fact directly storedon the integrated peripheral 1. These files can be accessed in read, andfor certain ones in write in order to allow the end user to change theglobal parameters of the equipment which he controls, or to allowverification of the authenticity to third parties by inputting theparameters. This method can also be used for changes in data systems,identifiers or passwords during the initialisation phases(identification, authentication, activation).

As a suggestion for non-limiting implementation, the virtual files cancontain:

-   -   78: the internal date 6, possibly associated with important        dates, such as the date when the time was first set, and the        authentication date,    -   79: the internal electronic serial number 8,    -   80: the authentication elements,    -   81: the system parameters, the writing making it possible to        effect certain optional operating modes which are programmable        by the user (by way of example, time zone, expiry, control and        access limitation . . . ),    -   82: the state of the system,    -   83: the log file of exceptional events,    -   84: the elements monitored by the equipment, internal voltages,        temperatures, in the case of a SMART hard disk (Self-Monitoring,        Analysis and Reporting Technology),    -   85: the contents of the ROM memory,    -   86: the contents of the RAM memory,    -   87: the ‘manufacturer's’ identification elements.

It is recommended that all these files are easily readable by a humanoperator and are printable (use of an alpha-numeric code, for examplebase 64, with limitation of the number of characters per line or evenHTML or XML standards).

The following example illustrates the operation of the virtual files:the authentication file 80 is encoded in order to be easily editable ina reserved system file named by way of example <AuthChek.sys>. Writingis possible if the anti-analysis temporisation conditions are fulfilled88. Writing to this file triggers the internal calculation of one of theauthentication elements, depending upon the nature of the written file:

-   -   empty file 89,    -   file containing a formatted input message 68,    -   file containing exactly the unique secret identifier 17.

In read, the system returns, at the end of calculation, a file of fixedlength and structure comprising in association, according to thepreviously clarified methods, a formatted message which is ready to besent for verification, and including all the necessary elements forverification: a fixed length fingerprint, the serial number, the messageused, the date used.

As an option or variant, in the case where the application requires anafterglow of data which is much less than the subjective or objectivelifespan of the equipment, an expiry option can make it possible to freefrom the place on the medium, by destroying if necessary automatically,the obsolete files in the past relative to the internal clock. Theoperability limits can be fixed either by constructional design or bythe entitled authenticating body, or during initial start-up by the enduser, and can comprise limitations on the freed space, such as forexample necessarily protecting a fraction of the total capacity. Theexpiry is expressed typically in the number of days relative to thepresent, such as dated by the internal clock, and can be adjusted tocalendar events (beginning or day of the week, beginning or day of themonth, beginning or day of the year). Internal dating in universal timemeans that at least one day of margin is systematically added in orderto take into account the time lag in local time and the drift of theinternal clock.

The various modes of operation connected to the expiry are clarified inFIGS. 11 to 16. The storage space is represented in the form of arectangle.

The storage space is initially empty 90.

The addition of new files 91 progressively fills the storage space. Thepreviously written data are protected against alteration 4, the new filetakes its place in the free space 5 and is dated at the end of writingto the current internal date 26, thus increasing the protected occupiedspace 4.

The files therefore sequentially fill the storage space in the course oftime 92.

In the mode of operation without expiry, the storage space is filledcompletely: any attempt to write a file which exceeds in capacity theremaining free space is rejected and reports an error 93.

The mode of operation with expiry is clarified hereafter. The expiryterm determines a pointer 94, on this side of which the data can bedeleted uniquely if necessary. When the peripheral is full, a file witha size larger than the available free space can be added, by integrallydeleting one or more files which have expired. The file which was notable to be written due to a lack of free space can then be stored byzapping the bare minimum of files which have expired, even if it meansbeing split into two non-contiguous parts 95, 96. The files are deletedcompletely, thus leaving possibly a surplus free space 5, the size ofthe new written file not being necessarily exactly identical to the sizeof the old zapped files.

Other files can be added according to the same principle 97. The systemprotects the old files beyond the expiry term. If writing the new fileinvolves destruction of a file not fulfilling the expiry terms, theperipheral is considered as ‘full’, the operation is annulled 98 andreports an error.

In the case where the expiry mechanism is implemented, the storage spacehas a circular structure 99 contrary to the standard linear structure 92without expiry.

The peripheral reports a virtual free space corresponding to the spaceliberated potentially by zapping the totality of files which have‘expired’.

The medium can advantageously be partitioned with a variable expiryduration. Once programmed, the expiry duration cannot be changed.Partitioning advantageously allows management on different logic unitsof different expiry durations. The partitioning can be fixed:

-   -   number of partitions fixed at activation by the user, then size        of partitions fixed.

The partitioning can be dynamic:

-   -   number of partitions variable but limited (no data or active        partition can be deleted in the totality of the partitions).

According to a particular embodiment connected to the current state ofthe art, available interfaces and the existence of current basecomponents, FIG. 17 shows a more detailed synopsis of a suggestion forimplementation based as a non-limiting example on a hard disk 100.Likewise, the described operational splitting does not necessarilyreflect the structure of the components which are used, each functionbeing able to be, in future implementations, distributed or integrateddifferently. By way of example, it is perfectly conceivable to integrateall or part of these functions in the internal electronic systemintegrated in the hard disk, which already comprises, in currentimplementations, a controller which is able to cover a part of therequested functions by alteration of the micro-code.

The controller as defined is based on an interface (bridge) component101, normally integrating a processor which is able to run a programmeinterpreting the commands, and usually, two standard interfacecontrollers for storing data 102, 103. In order to ensure optimalperformance, these special controllers have specific material resourcesinternally which are optimised in order not to impair the overallperformance with respect to the transfer of data. By way of non-limitingexample in view of the constant development of standards in thisrespect, there are intelligent converters for the external interfaces105 of the FireWire/USB/Ethernet/SerialATA type to peripheral storageinterfaces ATA, IDE, SerialATA 102. According to the standard used, aspecific active physical interface can be integrated or entrusted to anexternal component 104 according to the transmission technology which isused.

This controller must be able to address a non-alterable internal orexternal programme memory in ROM (ROM or OTP One Time Programmable) 106,and a data memory in RAM (107) safeguarded by battery 108 withoutexternal supply thanks to a commutation device 109, or possibly based ona Flash type memory or on a combination of the two technologies.

The functional and operational micro-code, apart from the initialisationphase, is uniquely in ROM and can be neither altered nor updated. Theinitialisation micro-code is pre-loaded in the data memory 107 duringmanufacture and destroyed before activation in an irreversible manner.

No programme or micro-code can be loaded by the standard interfaces.

The operational data memory is safeguarded in order to keep thetemporary or non-critical intermediate parameters of the state of thesystem, and/or the history of past operations (journal or ‘log’) orcurrently in the case of a break in external supply. The controller 101does not need to be supplied autonomously.

An independent controller 110 can be associated with the controller 101,allowing monitoring of the internal state of the system with or withoutany external supply source, itself supplied also by battery 108. Themonitoring controls the state of the equipment, the voltages of theinternal batteries and possibly other significant physical parameters(temperature). It is capable of ordering an external indicator 111(light/LED) to interface, giving visually the state of the system evenwithout supply, and is able to warn of faults in the equipment or itsinvalidation. The state of validity of the equipment indicated by thismeans must be correlated by other methods of investigation duringsupply.

The controller 101 indirectly addresses a volatile memory component/realtime clock 112, comprising a volatile memory which can be deleted by anexternal signal 119. These components natively manage a supplysafeguarded by battery 113 connected to their permanent functionality.The real time clock is associated with an oscillator compensated intemperature with low consumption 114, itself also safeguarded by battery115. It is the stability of this oscillator which determines the maximumdrift of the clock. By way of example, there are compatible compensatedoscillators with a battery supply which ensure a guaranteed drift lessthan 1 minute per year, which is reasonable and not particularlycritical insofar as the drift can be measured at any moment.

The integrated deletable memory contains the unique identifiers: serialnumbers 8 and unique secret identifier 7, as well as possibly otherparameters judged to be critical (pointers . . . ).

The real time clock assembly 112, 114 is secured by a sequential logic116 which can be integrated in a programmable logic component with lowconsumption supplied by battery 113. This logic manages theinitialisation modes, the operational mode and the mode for destructionof unique parameters and integrates an operational machine 117 ensuringthe unique irreversible sequencing of operations.

At initialisation, the sequencer 116 assists the described process andensures sequential protection in write of the parameters before beinginitialised once and once only (clock, identifiers) into the component112.

The initialisation sequence can be unfolded once, from an unstable stateforced artificially during manufacture, the passage to the followingstate being ensured by the controller until the operational state, thenpossibly the invalidation state. Break in the safeguarded supply ordetection of intrusion resets the operational machine in an initialstate corresponding to the invalidation state of the equipment.

Functionally, the sequencer 116 ensures the temporised materialprotection in read of the unique secret identifier, by authorising itsaccess in a limited temporised manner via the real time clock to, forexample, once per 24 hours.

In the case of detection of intrusion or a supply fault, it ensuresinhibition of the real time clock by blocking the oscillator 114 towardsthe latter, and re-ensures the invalidation of the identificationparameters which are possibly not deleted. Access to the serial numberand to the clock in read from the controller remains possible, theaccess in read to the unique deleted identifier is definitivelyinhibited for invalidation control and any write access.

The intrusion alert system 118 is connected to the intrusion sensorwhich is used and permanently checks the electrical parameters of thesensor (resistor 121, capacitor 122, short circuit or open circuit 123)and also the temperature 120. This part is entirely autonomous andself-supplied by battery 124. A state of alert, or the absence of supplyby battery 124 deletes 119 the volatile memory containing theidentifiers 112 and reinitialises the logic element 116 which moves intoan invalidated equipment state.

The system is supplied for the operating part by external power supply125, 14, possibly backed-up by cut-out converters or voltage regulators126 which generate internal supply voltages for the equipment. Thepermanent supply saves on internal batteries thanks to an electronicswitching system 127 which uses the external supply 125 as a priority,an optional external auxiliary battery 128, and finally as a last resortthe internal batteries 108, 113, 115, 124 which makes it possible toextend the lifespan of the equipment, essentially limited by thelifespan of these internal batteries.

The number of internal batteries depends upon the consumption andoperational independence of each sub-assembly. The distribution is givenpurely indicatively.

The battery of the intrusion detector is possibly doubled forredundancy, but remains independent of any other internal supply source.

The components 100 to 106 are supplied only by the main external source.

The external interfaces such as the supplies, the input/output buses,the control signals are protected from excess voltage, excess currentand are filtered 129 in order to avoid that the system can be impairedby a defective source, or voluntarily by application of extreme levelswhich are able to put the equipment into an unknown state ofvulnerability.

The RAM 106 used by the controller must at no time comprise a consistentpartial copy of the secret internal identifier 7.

The totality of the internal elements is sunk in an electricallyinsulating and thermally conductive resin 130.

A non-secure second casing 131 protects the totality of the equipmentagainst shocks in order to avoid any false accidental alarm, carries thewearing interfaces (mechanical, connection interfaces), the auxiliaryinterchangeable battery, the visual indicators (lights) and possiblysound indicators (buzzer), and makes it possible to improve theaesthetic and/or external ergonomic appearance. This double casing mustleave visual access to the external serial number and must be easilyremovable in order to be able to effect control of the integrity of theequipment by itself. The double casing can be adapted for usage of theperipheral: removable peripheral or fixed in a standard 3½″ or 5¼″drawer, external peripheral, peripheral integrated into a portable,individual or server computer.

The depressurisation capsule of the hard disk is carried by a conduit132 to the outside of the enclosure 10 without impairing thevulnerability (connection piece and capillarity).

The following devices and methods are able to be implementedadvantageously and are listed without being exhaustive:

An auxiliary serial interface 133 can allow independent limited accessto the controller in the case of failure of the main input/outputoperating interface 105, in order to analyse the authenticity andvalidity of the equipment, or can be used for advanced access control orsecure copy functions by interfacing, by way of example a smart card.

It is necessary to provide a certified method for transmission of datawith preservation of the legal validity: authenticity and dating. By wayof example, this can be implemented using an external cryptographicmethod of signature and of digital certification. An interface of the‘smart card’ type can be used likewise in this case with a cryptographiccard authenticating the transfer of data from the source equipment totarget equipment using the internal date and the secret identifiers ofeach of the two.

According to a variant which is not necessarily implemented, in thetypical case where the controller runs an on-board programme or containsprogrammable circuits, the object code (possibly source) can bepublished and in fact can be checked.

According to a variant which is not necessarily implemented, it seemsuseful to include an autonomous system for protecting access to the databy the user by password or any other identification method (smart card),in order to inhibit upon request:

-   -   access to data in write    -   access to data in read (return of empty contents, by way of        example a ‘zero’ character chain)    -   the visibility of directories and file names    -   any access to the files

According to a variant which is not necessarily implemented, it is wiseto include an internal system for limiting the filling quota which canavoid deliberate or accidental filling of the equipment (expressed byway of example in megaoctets per number of days) or can make it possibleto anticipate the replacement of the equipment for extending the storagecapacity.

According to a variant which is not necessarily implemented, it ispossible, according to the file system which is used, to provide apossibility for changing the name of the files and directories, in orderto facilitate use of the data in the past. This likewise provides thepossibility of modifying the tree structure of the directories and anymovement of logic data insofar as this has no influence on the contents,nor the date, nor possibly on extending or making versions of the files.Renaming of the files can be implemented, only the basic header cannotbe altered: renaming the long name, without tampering with the shortname (8.3 characters in numerous usage systems). The displacement offiles can be implemented: directory changing, without tampering withdata.

One means of protecting in read can advantageously be implemented bypartition, ensuring the protection of the confidentiality of the data,the commutation of this function can be controlled by password or smartcard, and by partition.

The described device is particularly adapted to private storage andarchiving of computer data which are likely to have authentic, juridicaland/or legal evidential value before authorised authorities.

1-16. (canceled)
 17. Method for storing computer data, characterised inthat it comprises integrating entirely in one device: a data storageperipheral (1), an adapted input-output controller (2) transforming saiddata storage peripheral (1) into a single- or restricted-write storageperipheral by diverting all input-output interface (13) commands from ahost system (20) to the internal interface (3) of the integrated datastorage peripheral (1), in order: to authorise exclusively the additionof new files in the free space (5) by dating them independently thanksto a secure internal real time clock (6), and to prohibit the deletion,alteration and rewriting of previously written and hence prior dateddata (4), to protect the totality of said device on the one hand againstforgery or duplication by a unique secret internal identifier (7) byassociation with a unique public serial number (18), on the other handby a peripheral protection enclosure (10) intended to prevent intrusioninto the equipment, the alteration of any component and internal data,and also the analysis of the unique secret identifier withoutcompromising the validity and authenticity in an irremediable manner, todetect said intrusion, alteration and analysis attempt, said detectionsbeing able to be verified by several third party methods on saidprocess, the latter being thus secure and suitable for storingauthenticated, dated computer data with an evidential value, and in thatit comprises furthermore making it possible to guarantee the unique,unreproducible personalisation of the equipment whilst publishing itsexistence, possibly before authentication, by generating randomly bycalculation internally of the equipment, said unique secret identifier(7), by calculating internally a one-way digital fingerprint (23) of theunique secret identifier (7) which does not allow return to the latter,by establishing the uniqueness of the fingerprint by interrogation of apublic database (21) containing the fingerprints of the totality ofexisting equipment, the identifier being recalculated if there is aclash and the device being formally identified as soon as thefingerprint is unique, by adding therefore into the public database (21)the references of the equipment: unique serial number and fingerprint(23).
 18. Method according claim 17, characterised in that it comprisesreproducing electronically and internally (8) said unique public serialnumber in order to allow electronic control of the latter.
 19. Methodaccording to claim 17, characterised in that it comprises furthermorephysically protecting all the internal components by leaving accessibleonly the external functional input-output (13) and supply (14)interfaces, thanks to a peripheral sealed enclosure (10) encompassingall the components, formed by a passive mechanical and electromagneticprotection (11) incorporating an active intrusion detection sensor (12)and the associated electronic system (9), the latter ensuring theimmediate destruction of the unique secret internal identifier (7) andthe internal serial number (8) if necessary, by instantaneous deletion,in the case of voluntary or involuntary deterioration changing thevulnerability or the autonomy of the device, or any internalinvestigation attempt detected by the sensor (12) being able to make itpossible to compromise, control, alter, analyse data, interfaces orinternal components.
 20. Method according to claim 19, characterised inthat it comprises furthermore keeping active the internal real timeclock (6), the secret identifier (7), the internal serial number (8) ifnecessary and the electronic system for detection of intrusion anddestruction (9), without any external supply source for the lifespanspecified for the equipment, thanks to an autonomous internal supplysub-system (15), possibly backed-up externally in order to extend thelifespan thereof.
 21. Method according to claim 17, characterised inthat it comprises furthermore ensuring the authenticity of the deviceafter manufacture, the test, the final assembly and the activation ofthe peripheral protection (9), until acquisition by the end user, bymaking unique the operations for assigning the unique serial number (8,18), the synchronisation of the real time clock (6) relative to anexternal trusted time reference (16), internal self-generation of theunique secret identifier (7), the external copy of the unique secretidentifier (17) in a secure environment of the unique secret identifierto an authenticating body (22) entitled to guarantee the secrecy of thisidentifier and in fact the authenticity of the equipment, the uniquenessof each operation being guaranteed by design by inhibiting ordestroying, in an irreversible manner and as soon as possible in theinitialisation sequence, the material elements and/or the micro-codeallowing this initialisation.
 22. Method according to claim 17,characterised in that it comprises furthermore allowing withoutlimitation on the occurrence, the preliminary verification of theauthenticity and of the integrity, by checking and cross-checking uniquelisted serial numbers (8, 18) in the public database (21), by checkingthe validity and the progress of the internal clock (6) relative to anexternal trusted time reference (16), taking into account the maximumspecified drift of the internal clock, and by visual or non-destructivechecking of the integrity of the external casing (12).
 23. Methodaccording to claim 21, characterised in that it comprises furthermoreallowing authorised bodies to authenticate the equipment upon request byverification via third party methods using the secret internalidentifier (7) without revealing it, by internally recalculatingdynamically the fingerprint of the identifier (23) and by directlyinterrogating the public database (21), or by internally connecting thesecret identifier to the internal date (6) and to an external messageprovided before internal calculation of the fingerprint of the totality,the totality of known elements being provided for authenticationremotely by the entitled authenticating body (22) which alone can verifythe consistency thanks to the copy of the unique secret identifier (17)which it has, these functions involving the secret identifier beingtemporised and limited in occurrence internally of the equipment inorder to avoid inverse determination of the identifier by analysis orsuccessive attempts.
 24. Method according to claim 21, characterised inthat it comprises furthermore allowing the authenticating body (22)itself to authenticate the equipment under its control and as a lastresort by injecting its copy of the secret identifier (17) forcomparison internally of the equipment which detects perfect similarity,and sends in reply a unique message which can be verified by saidauthenticating body (22), this function involving the secret identifierbeing temporised and limited in occurrence internally of the equipmentin order to avoid inverse determination of the identifier by analysis orsuccessive attempts.
 25. Method according to claim 17, characterised inthat it comprises furthermore allowing, by way of variant which is notnecessarily implemented, managing autonomously the expiry of data in thepast, by authorising, solely in the case of complete filling of theinternal storage peripheral (1), writing of new files by zapping, withinsufficient limits and in chronological order, data prior to a relativedate (94), updated dynamically relative to the current date provided bythe internal clock (6), departing thus from the single-write rulewithout however compromising or altering the useful data which are stillvalid and dated subsequently to the expiry date.
 26. Method according toclaim 17, characterised in that it comprises furthermore presenting anyinternal parameter and indicator which is characteristic of and specificto said device in the form of virtual files in reserved names, seen bythe host system as standard files and avoiding using drivers orparticular operating modes at the level of the host system formanagement, administration and monitoring of said device.
 27. Methodaccording to claim 17, characterised in that it comprises furthermorepartitioning said data storage peripheral with a different expiryduration by partitioning.
 28. Device for storing computer data,characterised in that it integrates in full: a data storage peripheral(1) comprising an internal interface (3), an adapted input-outputcontroller (2), an input-output interface (13), a secure internal realtime clock (6), a unique secret internal identifier (7), a unique publicserial number, a peripheral protection enclosure (10), said adaptedinput-output controller (2) being able to transform said data storageperipheral (1) into a single- or restricted-write storage peripheral bydiverting all input-output interface commands (13) from a host system(20) to the internal interface (3) of the integrated peripheral (1), inorder: to authorise exclusively the addition of new files in the freespace (5) by dating them independently thanks to the secure internalreal time clock (6), and to prohibit the deletion, alteration andrewriting of previously written and hence prior dated data (4), meansfor guaranteeing the unique, unreproducible personalisation of theequipment whilst publishing its existence, possibly beforeauthentication, by generating randomly by calculation internally of theequipment, said unique secret identifier (7), by calculating internallya one-way digital fingerprint (23) of the unique secret identifier (7)which does not allow return to the latter, by establishing theuniqueness of the fingerprint by interrogation of a public database (21)containing the fingerprints of the totality of existing equipment, theidentifier being recalculated if there is a clash and the device beingformally identified as soon as the fingerprint is unique, by addingtherefore into the public database (21) the references of the equipment:unique serial number and fingerprint (23), the totality of said devicebeing protected on the one hand against forgery or duplication by theunique secret internal identifier (7) by association with the uniquepublic serial number, on the other hand by the peripheral protectionenclosure (10) preventing intrusion into the equipment, the alterationof any component and internal data, and also the analysis of the uniquesecret identifier without compromising the validity and authenticity inan irremediable manner, intrusion, alteration and analysis attemptsbeing able to be verified by several third party means on the totalityof said device, the latter being thus secure, inviolable andforgery-proof, suitable for storing authenticated, dated computer datawith an evidential value.
 29. Device according to claim 28,characterised in that it comprises a serial number reproducedelectronically and internally (8) reproducing said unique public serialnumber.
 30. Device according to claim 28, characterised in that itcomprises means for physically protecting all the internal components byleaving accessible only the external functional input-output (13) andsupply (14) interfaces, thanks to a peripheral sealed enclosure (10)encompassing all the components, formed by a passive mechanical andelectromagnetic protection (11) incorporating an active intrusiondetection sensor (12) and the associated electronic system (9), thelatter ensuring the immediate destruction of the unique secret internalidentifier (7) and the internal serial number (8) if necessary, byinstantaneous deletion, in the case of voluntary or involuntaryimpairment changing the vulnerability or the autonomy of the device, orany internal investigation attempt detected by the sensor (12) beingable to make it possible to compromise, control, alter, analyse data,interfaces or internal components.
 31. Device according to claim 29,characterised in that it comprises means for keeping active the internalreal time clock (6), the secret identifier (7), the internal serialnumber (8) if necessary and the electronic system for detection ofintrusion and destruction (9), without any external supply source forthe lifespan specified for the equipment, thanks to an autonomousinternal supply sub-system (15), possibly backed-up externally in orderto extend the lifespan thereof.